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----- Original Message ----- From: <Lehanover@aol.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, April 20, 2005 10:03 AM
Subject: [FlyRotary] Re: Single Rotor Balance
In a message dated 04/20/2005 11:42 Central Daylight Time,
fosborn@infowest.com writes:
<< I realize this is a bit of a quibble but with the increasing interest in
single rotor
engines there should be adequate recognition that balancing one is not easy.
Balance Diagram courtesy of PL's ACRE NL.
With all due reverence, Lynn.
Fred O. >>
Sounds good to me.
Include the entire assembled weight of the rotor less the apex seals and apex
seal springs.
A balance person might add in that a slight imbalance to account for
compression and power stroke may make things smoother. I have never built one so I
advise the assistance of those who have.
Lynn E. Hanover
My single rotor is running with analytical balance only. The main reason for doing that was to get the test rig running without having to spend time and money for machine balancing. As it turned out, it is sufficient for a start.
I see three steps in the balancing quality. The first one is calculated balance, considering rotor with seals, and balance weights. The second is, rotor with seals, rotor CG offset due to stationary gear, oil in rotor, balance weights exact location. I believe the second step is a precondition to the third step in order to come close to what the balancing machine can handle.
On my engine, the first step gave me acceptable running quality for up to 4500RPM, which was more than sufficient for the testing scope. I made a new, lighter flywheel, which I have run briefly, and the engine is running even better than with the first one (pure luck). With the mods going into the parts now, like shorter e-shaft and final design side housing, the flywheel and counter weight locations are fixed, I am ready for step 2. In this effort I am using more sofisticated moment measurement procedures than in the first step.
I am expecting to be able to do most of the testing, including 7500RPM before goning to a balancing machine.
Richard Sohn
N-2071U
Homepage: http://www.flyrotary.com/
Archive: http://lancaironline.net/lists/flyrotary/List.html
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